Method and means of heat protection for metal-to-glass seals



Jan. 28, 1941. Q GQQDALE 2,229,734

METHOD AND MEANS OF HEAT PROTECTION FOR METAL-TO-GLASS SEALS Filed June 8, 1940 2 Sheets-Sheet l INVENTOR. LYMV csaomu;

ATTZRNEY.

1941- L. c. GOODALE 9 973 METHOD AND MEANS OF HEAT PROTECTION FOR METAL-TOGLASS SEALS Filed June 8, 1940 2 Sheets-Sheet 2 III INVENTOR. L MW! e: 5001mm Patented Jan. 28, 1941 2,229,734

UNITED STATES PATENT OFFICE METHOD AND MEANS OF HEAT PROTEC- TION FOR METAL-TO-GLASS SEALS Lynn 0. Goodale, Newark, N. J., assignor to Federal Telegraph Company, Newark, N. J., a corporation of California Application June 8, 1940, Serial No. 339,481

8 Claims. (01. 250-27.5)

This invention relates to methods and means for forming into a cooling fin for use on any for protecting metal to glass seals from heat electrode supporting rods. This blank is preconducted from the electrodes to the seals along pared from any suitable metal, such as molybthe electrode supporting rods. denum. At I the blank is made relatively nar- This problem is of great importance in power row so that the Width of the blank is approX- tube design since in said tubes a great deal of imately equal to the circumference of the rod heat is generated, and the failure of the metal to which it is to be applied. At the other end to glass seals is frequently the cause of tube 2 the blank is made much wider. The blank is failure. then bent into a cylindrical form as shown in 10 One form of protection commonly used is the Fig. 2 with one portion of it forming a substan- 10 heat shield which serves to deflect radiation heat tially cylindrical sleeve [0, while the wide poraway from the seal. These heat shields, howtion thereof forms two faces as indicated at II, ever, do not protect the seal in any way from contiguous one to the other. The formed blank the heat conducted along the electrode supportis then preferably fastened together by means ing rods. such as rivets l2, shown in Fig. 3. The rivet- 15 According to my invention I provide heat raing of the blank at this point, just above the diating fins fitted to said rods and integrally cylindrical portion tends to cause the faces l0 bonded thereto, preferably by welding, for radito diverge from one another, as can be more ating the conducted heat before it reaches the clearly seen in Fig. 6.

glass seal. The sleeve formed by the blank is so dimen- 20 Diiiiculty is encountered in attempting to weld sioned that it fits snugly over the electrode supthe metal fins or vanes to the supporting rods, porting rod [4, as shown in Fig. 4. The sleeve since these rods particularly when made of tungand rod are then welded together at one or sten as in most vacuum tubes, tend to warp or more points as shown at I5, Fig. 4. Figs. 5 and bend under the welding operation. In accord- 6 show enlarged sectional longitudinal and 25 ance with my invention I overcome this difficulty transverse sectional views of the cooling fins as by supporting the radiating fin on a sleeve, which applied to the rods to more clearly show the embraces a relatively long portion of the rod, structure. fitting the sleeve snugly over the rod and there- The supports are made of suitable material after spot welding the sleeve to the rod. This such as tungsten or molybdenum. If desired, 30

process avoids warping of the rods, presumably the metal forming the cooling fins may be subbecause the heat generated during the welding jected to sand blasting to increase the radiaprocess is distributed evenly along the rod. This tion eifect thereof. avoidance of warping is a very important prac- Figs. '7 and 8 show in a plan view and a crosstical problem in vacuum tube construction. sectional view, respectively, a vacuum tube elec- 35 It is an object of my invention to provide a trode supporting stem embodying cooling vanes method of welding a metal sleeve to a rod Within accordance with the principles of my invenout distorting the rod during the welding opertion. A portion of vacuum tube envelopes is ation. shown at 10 through which a plurality of fila- 40 It is a further object of my invention to proment electrode supporting rods H to 16, inclu- 40 vide a method and means for protecting the seal sive, are sealed. Other rods TI, 18 and '19 are in a vacuum tube from heat conducted over a provided for supporting additional electrodes or metal electrode supporting rod. for other auxiliary supporting functions. If de- A better understanding of my invention, as sired, the electrode supporting rods and the other well as other objects and features thereof may rods may be further braced by means of a glass 45 be had from the particular description of a pretruss or ring 80. ferred embodiment thereof made in connection In order to protect the glass seal from heat with the accompanying drawings, in which conducted down rods II to 16, each of these Figs. 1 to 6, inclusive, illustrate the successive rods is provided with a radiating fin assembly steps in providing a cooling fin welded to a rod, similar to that described in connection with 50 and Figs. 1 to 6, inclusive. These radiating fins H Figs. 7 and 8 show in plan and sectional view, are each mounted on a separate sleeve I0 and respectively, an electrode supporting stem in acare spot welded at one or more points as indicordance with my invention. cated at I4, Fig. 8, to the corresponding elec- In Fig. 1 is illustrated a metal blank suitable trode supporting rod. 55

Preferably, the spot welds are located at points intermediate the ends of the sleeve since by applying the welding heat at this point less danger of causing too severe a local heating of the supporting rod is encountered. It can be seen that heat generated in the electrode will be conducted down rods H to 16 to the radiating fins. Because of the intimate contacts between the supporting rods and the sleeves the heat will be readily conducted into the radiating fins and will thus be dissipated before reaching the metal to glass seal. Accordingly, the danger of damage to the tube by excess heating is greatly reduced. It is, of course, possible to use in combination with these cooling fins a heat shield to prevent radiated heat from reaching the glass seal if desired. However, it is generally found unnecessary to add aheat shield since the radiating fins may be spaced a considerable distance above the glass seal and therefore dissipate a large portion of the heat before danger of damage to the tube is encountered.

While I have described above a preferred embodiment of my invention, it should be distinctly understood that this is merely by way of illustration. The principles of my invention may be applied to arrangements for accomplishing a weld between a metal such as tungsten and a sleeve regardless of the partic ular application thereof. Furthermore, the general principles of utilizing cooling fins for protecting the vacuum tube seal from heat is considered to be a novel and patentable part of my invention.

What I consider as my invention and desire to obtain protection upon is embodied in the accompanying claims.

What I claim is:

1. The method of welding a metal sleeve to an electrode supporting rod without causing distortion of said rod during the welding process, which comprises fitting snugly around said rod a sleeve embracing a relatively long portion of said rod, and thereafter spot welding said sleeve and rod.

2. The method of welding a metal sleeve to an electrode supporting rod without causing distortion of said rod during the welding process, which comprises fitting snugly around said rod a sleeve embracing a relatively long portion of said rod, and thereafter spot welding said sleeve and rod at a point intermediate the ends of said sleeve.

3. The method of mounting a cooling fin on an electrode supporting rod which comprises, fitting a metal sleeve carrying cooling fins snugly around said rod, said sleeve embracing a relatively long portion of said rod and spot weldin said sleeve to said rod.

4. The method of mounting cooling fins on an electrode supporting rod which comprises providing a blank of metal sufliciently long to embrace a relatively long portion of said rod and having at least a portion greater than the circumference of said rod, bending said blank to form a sleeve having two oppositely facing surfaces from said portion, fastening said oppositely facing portions together, fitting said sleeve snugly over said rod and thereafter spot welding said rod and said metal blank.

5. The method of protecting vacuum tube seals from heat conducted along metallic electrode supports passing through said seals, which comprises fitting snugly around each of said leads a sleeve embracing a relatively long portion of said lead and carrying a metallic radiating fin, and spot welding said sleeves with said leads.

6. The method according to claim 5, wherein said sleeve is formed from a metal blank having a portion which is substantially of a width equal to the circumference of said lead, and a portion of greater Width, further comprising forming said blank into a sleeve with the portions thereof of greater width extending from one line in facing relation to one another, and fastening together said extending parts to provide a split radiating vane.

7. In a Vacuum tube electrode assembly comprising a glass envelope portion, a plurality of metal rods forming electrode supports and means sealing said rods through said glass, a means for protecting said glass seals from heat conducted along said supporting'rods comprising heat radiating fins integrally bonded to said rods at a point spaced from said glass seals.

8. In a vacuum tube electrode assembly comprising a glass envelope portion, a plurality of metal rods forming electrode supports and means sealing said rods through said glass, a means for protecting said glass seals from heat conducted along said supporting rods, a metal sleeve carrying a radiating fin snugly fitted around said rod, said sleeve embracing a, relatively long portion of said rod and spot welded thereto.

LYNN C. GOODALE. 

